205 research outputs found
An Elementary Fragment of Second-Order Lambda Calculus
A fragment of second-order lambda calculus (System F) is defined that
characterizes the elementary recursive functions. Type quantification is
restricted to be non-interleaved and stratified, i.e., the types are assigned
levels, and a quantified variable can only be instantiated by a type of smaller
level, with a slightly liberalized treatment of the level zero.Comment: 16 pages; correction
Resolution Trees with Lemmas: Resolution Refinements that Characterize DLL Algorithms with Clause Learning
Resolution refinements called w-resolution trees with lemmas (WRTL) and with
input lemmas (WRTI) are introduced. Dag-like resolution is equivalent to both
WRTL and WRTI when there is no regularity condition. For regular proofs, an
exponential separation between regular dag-like resolution and both regular
WRTL and regular WRTI is given.
It is proved that DLL proof search algorithms that use clause learning based
on unit propagation can be polynomially simulated by regular WRTI. More
generally, non-greedy DLL algorithms with learning by unit propagation are
equivalent to regular WRTI. A general form of clause learning, called
DLL-Learn, is defined that is equivalent to regular WRTL.
A variable extension method is used to give simulations of resolution by
regular WRTI, using a simplified form of proof trace extensions. DLL-Learn and
non-greedy DLL algorithms with learning by unit propagation can use variable
extensions to simulate general resolution without doing restarts.
Finally, an exponential lower bound for WRTL where the lemmas are restricted
to short clauses is shown
Chlorinated biphenyls and p,p'-DDE in Mediterranean surface waters
Individual chlorobiphenyls (CBs) and p,p'-DDE were determined in solution and suspension in surface transects of the open Mediterranean Sea in 1987. Large volumes of sea water (1400—1700 dm3) were analyzed.
Concentrations of CBs were low in solution (<5 pg/dm3) and in suspension (<60 pg/dm3). Values for their sum (XCB) were 1.7-43.9 and 190-615 pg/dm3, respectively. Compositions of the CB mixtures in solution as well as those in suspension were very similar in the various transects, but considerable differences were present between solution and suspension in each transect. It was attempted to interpret these differences in terms of molecular characteristics (octanol-water distribution coefficients, Kaw). The resulting plots of log Kovl vs. the apparent distribution coefficient (log K&) gave evidence for the uptake of CBs by suspended particles, followed by sedimentation out of the surface layer.
Concentrations in solution were much lower (1-2 orders of magnitude) than those reported before. This may result from improvements in the sampling and analytical techniques.
No clear evidence for significant local sources of these compounds was detected in the surface waters, as the levels in solution were very similar to the very low concentrations in the adjacent open Atlantic
Chlorinated Biphenyls and p,p\u27-DDE in Mediterranean Surface Waters
Individual chlorobiphenyls (CBs) and p,p\u27-DDE were determined in solution and suspension in surface transects of the open Mediterranean Sea in 1987. Large volumes of sea water (1400—1700 dm3) were analyzed.
Concentrations of CBs were low in solution (<5 pg/dm3) and in suspension (<60 pg/dm3). Values for their sum (XCB) were 1.7-43.9 and 190-615 pg/dm3, respectively. Compositions of the CB mixtures in solution as well as those in suspension were very similar in the various transects, but considerable differences were present between solution and suspension in each transect. It was attempted to interpret these differences in terms of molecular characteristics (octanol-water distribution coefficients, Kaw). The resulting plots of log Kovl vs. the apparent distribution coefficient (log K&) gave evidence for the uptake of CBs by suspended particles, followed by sedimentation out of the surface layer.
Concentrations in solution were much lower (1-2 orders of magnitude) than those reported before. This may result from improvements in the sampling and analytical techniques.
No clear evidence for significant local sources of these compounds was detected in the surface waters, as the levels in solution were very similar to the very low concentrations in the adjacent open Atlantic
Width and size of regular resolution proofs
This paper discusses the topic of the minimum width of a regular resolution
refutation of a set of clauses. The main result shows that there are examples
having small regular resolution refutations, for which any regular refutation
must contain a large clause. This forms a contrast with corresponding results
for general resolution refutations.Comment: The article was reformatted using the style file for Logical Methods
in Computer Scienc
Joint Communication, Sensing and Localization for Airborne Applications
With the upcoming trends in autonomous driving and urban air mobility, the
number of self-navigating vehicles will increase, since they are foreseen for
deliveries as well as autonomous taxis among other applications. To this end, a
multitude of on-board systems for wireless communication, environment sensing,
and localization will become mandatory. This is particularly true for unmanned
aerial vehicles (UAVs), since participation in the airspace requires
compatibility to and safe interaction with established users. A certain number
of systems are already in-use and occupy defined spectra as well as
installation space, which limits the freedom in the design of new systems. The
miniaturization of aerial vehicles like drones for delivery services further
reduces the degrees of freedom, especially in terms of size and weight of any
additional equipment. Hence, in this paper a joint approach of the design of
joint communication, sensing and localization for UAVs is discussed. Towards
this goal, multi-mode multi-port antennas and joint waveform design are
proposed as a part of the solution, when elevating autonomous driving to the
third dimension
In search of suitable reference genes for gene expression studies of human renal cell carcinoma by real-time PCR
<p>Abstract</p> <p>Background</p> <p>Housekeeping genes are commonly used as endogenous reference genes for the relative quantification of target genes in gene expression studies. No conclusive systematic study comparing the suitability of different candidate reference genes in clear cell renal cell carcinoma has been published to date. To remedy this situation, 10 housekeeping genes for normalizing purposes of RT-PCR measurements already recommended in various studies were examined with regard to their usefulness as reference genes.</p> <p>Results</p> <p>The expression of the potential reference genes was examined in matched malignant and non-malignant tissue specimens from 25 patients with clear cell renal cell carcinoma. Quality assessment of isolated RNA performed with a 2100 Agilent Bioanalyzer showed a mean RNA integrity number of 8.7 for all samples. The between-run variations related to the crossing points of PCR reactions of a control material ranged from 0.17% to 0.38%. The expression of all genes did not depend on age, sex, and tumour stage. Except the genes TATA box binding protein (<it>TBP</it>) and peptidylprolyl isomerase A (<it>PPIA</it>), all genes showed significant differences in expression between malignant and non-malignant pairs. The expression stability of the candidate reference genes was additionally controlled using the software programs geNorm and NormFinder. <it>TBP </it>and <it>PPIA </it>were validated as suitable reference genes by normalizing the target gene <it>ADAM9 </it>using these two most stably expressed genes in comparison with up- and down-regulated housekeeping genes of the panel.</p> <p>Conclusion</p> <p>Our study demonstrated the suitability of the two housekeeping genes <it>PPIA </it>and <it>TBP </it>as endogenous reference genes when comparing malignant tissue samples with adjacent normal tissue samples from clear cell renal cell carcinoma. Both genes are recommended as reference genes for relative gene quantification in gene profiling studies either as single gene or preferably in combination.</p
The Ability of Quantitative, Specific, and Sensitive Point-of-Care/Chair-Side Oral Fluid Immunotests for aMMP-8 to Detect Periodontal and Peri-Implant Diseases
The analysis of the disease-specific oral and systemic biomarkers in saliva and oral fluids (i.e., mouth rinse, gingival crevicular fluid (GCF), and peri-implantitis fluid (PISF)) is demanding. Several hosts and microbial factors may influence their expression, release, and levels. The type of saliva/oral fluids utilized for the diagnostics affects the analysis. High sensitivity and specificities together with sophisticated methods and techniques are essential for valuable outcome. We describe here recently developed practical, convenient, inexpensive, noninvasive, and quantitative mouth rinse and PISF/GCF/chair-side/point-of-care (PoC) lateral-flow aMMP-8 immunoassays (PerioSafe and ImplantSafe/ORALyser) to detect, predict, and monitor successfully the course, treatment, and prevention of periodontitis and peri-implantitis, respectively. The tests have been independently and successfully validated to differentiate periodontal and peri-implant health and disease in Finland, Germany, Netherland, Sweden, Turkey, Nigeria, Malawi, and USA. The clinical use of salivary/oral fluid biomarkers to identify oral and systemic conditions requires additional studies utilizing these noninvasive screening, diagnostic, and preventive aMMP-8 PoC/chair-side technologies.Peer reviewe
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